Introduction In 2017, the U.S. Food and Drug Administration (FDA) approved 5-aminolevulinic acid (5-ALA) as an intraoperative optical imaging agent in patients with suspected high-grade gliomas (HGGs). However, the application of 5-ALA for low-grade gliomas is still less accepted. Astrocytoma, isocitrate dehydrogenase (IDH) mutant tumors are diffuse infiltrating astrocytic tumors where there is no identifiable border between the tumor and normal brain tissue, even though the borders may appear relatively well-marginated on imaging. Generally, it is considered that 5-ALA cannot pass through a normal blood-brain barrier (BBB). Thus, 5-ALA fluorescence may mean disruption of BBB in grade II glioma. Case Report A 74-year-old male patient was diagnosed with a right parietal lesion suggestive of a low-grade brain tumor in a surgical resection using 5-ALA, which led to the detection of tiny fluorescence spots during the surgery. The frozen section was consistent with diffuse astrocytoma, IDH-wildtype (World Health Organization [WHO] grade II). The patient's postoperative magnetic resonance imaging (MRI) showed complete resection. Eight months after surgery, he began experiencing symptoms again and was admitted with a brain MRI finding consistent with recurrent infiltrating astrocytomas. This required reoperation of the brain tumor resection with 5-ALA. Unlike the first surgery, they observed a high fluorescence intensity; the pathological finding was glioblastoma, IDH-wildtype (WHO grade IV). Postsurgical brain MRI showed total resection of the tumor. The patient was discharged 4 weeks after surgery and continued with specialized clinical follow-up. Conclusion The use of 5-ALA continues to be a great contributor to the improvement in complete resection of primary brain tumors, especially HGG. Besides, fluorescence is increasingly approaching its use as a prognostic tool for aggressive clinical course, regardless of the initial grade of the tumor. This case report is an effort to expand knowledge for potentially using 5-ALA to help prognosticate brain tumors. Nevertheless, more clinical prospective studies must be conducted.